Superconductivity in textured Bi clusters/Bi2Te3 films

We report superconductivity at an onset critical temperature below 3.1 K in topological insulator ∼200-nm-thick Bi2Te3 thin films grown by pulsed laser deposition. Using energy-dispersive X-ray spectroscopy elemental mapping and Auger electron spectroscopy elemental depth profiling, we clearly identified bismuth (Bi) precipitation and Bi cluster signatures. Superconductivity in the Bi2Te3 films was attributed to the proximity effect of Bi clusters precipitated on the surface of the Bi2Te3 films.